<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <script type="module">
        let username = "jack";
    </script>
    <script type="module">
        let age = 20;
        // let username = 'lili';
    </script>

</body>

</html>